WIP: add a grafanaApp target to generate playlist like code

[charandas]

Here is a first take at generating equivalent code to how playlist currently looks in grafana.

Next up, I need to make the playlist watcher like generation also happen over here under the same target.

Removing codegenPath from this Jenny

I am not sure of how codegenPath could be useful for how Grafana's repo is currently setup. codegenPath is . as I see it, whether I invoke the sdk from within apps/playlist or I sit at the apps directory and do:

 grafana-app-sdk project component add --cuepath ./playlist/kinds --path ./playlist grafanaApp
 
 # alterntively, invoke it from within apps/playlist dir
 grafana-app-sdk project component add grafanaApp

Having a . codegenPath is unnecessarily complex for the template when pkgs are imported.

Removing kindsAreGrouped from this Jenny

Is there a real use case in Grafana for that or can we safely assume that they won't be? Not having this boolean makes the template so much easier on the eyes.

Example output

The outputted app.go looks like this gist with some commentary on the extra curly braces that I don't like.